1. Technical Field
The present invention relates generally to digital image collections, and more particularly to identifying popular landmarks in large digital image collections.
2. Background Art
With the increased use of digital images, increased digital storage capacity, and interconnectivity offered by digital media such as the Internet, ever larger corpora of digital images are accessible to an increasing number of people. Persons having a range of interests, from various locations spread throughout the world, take photographs of various subjects and make those photographs available for others to view, for instance, on the Internet. For example, digital photographs of various landmarks and tourist sites from across the world may be posted on the web by persons with different levels of skill in taking photographs. Such photographs may show the same landmark from different perspectives, under different conditions, and/or from different distances.
The vast number of such images available can be useful as an indicator of, or guide to, popular landmarks. To leverage information contained in these large corpora of digital images, it is necessary that the corpora be organized. For example, at digital image web sites such as Picasa Web Albums (from Google Inc., Mountain View, Calif.), starting at a high level menu, one may drill down to a detailed listing of subjects for which photographs are available. Alternatively, one may be able to search one or more sites that have digital photographs. Some tourist information websites, for example, have downloaded images of landmarks associated with published lists of popular tourist sites.
Most conventional digital photograph organizing systems rely on users to tag photographs. As numerous new photographs are added to these digital image collections, it may not be feasible for users to manually label the photographs in a complete and consistent manner that will increase the usefulness of those digital image collections. A system that can automatically extract information (such as the most popular tourist destinations) from these large collections is described in U.S. patent application Ser. No. 12/119,359 titled “Automatic Discovery of Popular Landmarks,” also assigned to Google Inc., California. The system described in application Ser. No. 12/119,359 uses a processing pipeline comprising a clustering stage based on geo-coding, and a clustering stage based on matching visual features of the images. What is needed, however, are other approaches to automatically discover landmarks and annotate images containing landmarks.